The present invention relates to a two-purpose power supply device which can be connected to the external power input socket of a mobile computer by a cable, or directly inserted into the battery chamber of a mobile computer to provide the necessary DC power supply.
The power supply for a mobile computer may be obtained from a rechargeable battery, or from city power supply through a power supply device. A mobile computer which uses battery power supply is free from the limitation of a stationary power supply. However, when the power of the battery drops below a certain value, the mobile computer become unable to work properly. If the power of the battery of a mobile computer is used up, it must be charged to the saturation state. Furthermore, conventional power supply devices are provided for connection to the external power input socket of a mobile computer, but they cannot be installed in the battery chamber of a mobile computer.